Seems to work decently on some systems, however some issues still needs to be corrected. Found another decent driver at http://www.usconverters.com
When installed on 10.4.11 I get lots of corrupt and missing data. I am running fairly flat-out at 57600 baud from a java app. The Prolific driver works fine for a while but then the machine locks solid so I was hoping for something better.
There are no 4 star reviews.